Generally, in times of an increasing number of applications providing radar sensing capabilities such as autonomous vehicles, there is a growing need of a method and a system for determining a permittivity of a substance layer with respect to materials used in this radar context especially to verify correct functioning of said applications in a highly accurate and efficient manner.
U.S. Pat. No. 3,694,742 discloses a device for measuring permittivity of materials on the basis of at least two different measured capacitance values of a capacitor connected to the material being tested and to a measuring oscillator the output of which is coupled to the input of a frequency meter in the form of a series combination of a switch and a pulse counter with a resetting unit, said capacitor being formed by at least two main electrodes permanently connected to the input of said measuring oscillator, and one additional electrode which is alternately connected by a changeover switch to one of said main electrodes in the course of measurement, while said resetting unit is connected to said pulse counter in the form of a reversible counter by an on-off switch actuated synchronously with said switch of the measured capacitor electrodes, the direction of counting of said reversible counter being determined by the position of said changeover switch of the measured capacitor electrodes. As it can be seen, due to the usage of said capacitor exclusively allowing for permittivity measurements with respect to materials of a higher thickness, the use of said device in the context of permittivity determination with respect to a substance layer disadvantageously leads to no useful result or a limited accuracy, and thus also to a reduced efficiency.
Accordingly, there is a need to provide a method and a system for determining a permittivity of a substance layer, each of which ensures both a high accuracy and an increased efficiency.